Twin-cupola process of making semisteel castings.



iii"). W33. 1

Snot ification of Letters Patent,

nppii atitt tilt-d 'i'eltri Be it krnan'n that l, JAM ns t. zen ol the United States, re in the county of Cool; and State ot' I new and in i\ .in- Tut oln Malling LSetnisteel (list ings, ol

have invented certa n provcnicnts lowing is a specification This invention relates to i=nnmveuients in the art of ma proportions ol' t quiremenrs in the stwni-stet -l,

tunbtiin steel st t the that or (trio-(ti portions t conmonent.parts tor it's intended uses.

*-; nn-thod l tion in the resulting: pro: forent. nielting' points ol' the tltttlti'lttl charged together in ti e eupoln. The p a. low melting point, is the itrst,

addixture l i and carbon i \:!J' ,o -;;it tye .rrnatte tron: heretol'ore :igiron and the in .-.ullieient la ited to .y oi the cunola and in ll (3 undetermined so as to of? the casting l ha we the )trsl adapted tas been found to he cry ontory, beunusottherc is so much. Variahit-t, due to the dilie' iron, having to u'ielt and Iliow to the bottom ol the cupoia, carrvingtelling between the with the htnu arphe't.

creases, thriolrv enuslu' in one ri at onlties rcstrt ha in which i praet i ed, \\'t distort: ol the sit-t l and our i-'o!t. and, at 2 a. subsequent tinn purpo. oi as possible, and pnttingthen. Llnou rend of t.

certain proportion ol the carbon steel sa lfor tne first tan.

:2 tonperature it) ,r amount ol the iirst one, lroin the bet t'tatv varying with rat; chargrlw; them into to the List, and hence nno sihlrto secure renit't t ua e liltii any h llL'lU lit nootiuu pro-'- less commonly teens-ids in what; I tori-til as below. de cribed, ttttttttttifi into pigs in order to ret a i Hi1 the inn-- he metal gi the e i "s 'aor th the (-upolu. h anothcr rocess ol Patented Feb. 5. 1907.

' nieltin re laratonw to (ftt. llllf the results ol sultant. a well as initial 1 ol proporti n:

n oi i: can be Ilttjt'ltll itnp nt-tit-e, to blonly a lair average as to the nnit ormity ol t lt} rttal when Past.

'lre object ot !n\' invention is to avoid the tmc rtaintr. and .nvn -unilormity and the reexpense ol the e prior metnods b enabling the production ol aslinggs ol' absolute nnil'ortni r as regards the proportion ol pig iron and carbon steel, \t'uit'h proportions may be vario'tl at o maintenance. not onl lin'otu iiout the enti e heat, but thr ugh any number ol heats ol tnis absolute unil'ormit lztthl by enabling the'continu ons production ol :-t.t!l-:l(( l castings ol prac tirall unil'orm qualities, proportions and as they hare brow-n These objects are attained bythe non practice in tire art liercinafter lully disclosed and set l orllt in the claims.

in carrying out my invention 1 use two independent eupolas. In; one cupoln 1 place pig iron, ol a given composition, and melted in the usual manner. In the other cupolit I plat-o carbon steel ol acomposition necessary to suit. the requirements of the casting, and melted as I do the pig iron. In this way both the iron and the steel are reduced to a molten state before being brought together and thedillinultyencountered in the old procin the lion-inter i 1, and second taps, ing point: of the pig iron tainod in the Wllllt iron.

esse by reason of the diil'crence in the meltand the carbon steel, is entirely obviated. As the composition ol the two metals is known, it becomes a very simple matter to tap,'l"ron1 one of the eupolas into a ladle, first a given amount, either by weight or measurement, of either molten pig iron or molten carbon steel, and utter-word tapping into the same ladle from the other cnpola the desired amount of either molten pig iron or molten carbon steel to till out the total amount containing predetermined proportions of pig iron and carbon steel.

1. have found in practice that the results may be improved by introducing about; fifty pounds ol white iron with each charm 01,

b sa about two hundred to seven hundred and lift pounds ol' carbon steel, the idea botu'ztl nznlornnty in to get the. benefit ol il'icreasod fluidity through the carbon a d manganese con- When the molten iron and steel are brought together in the ladle, a Workman, by the use of an iron bar, may thoroughly and efiectually complete the admixture oi the materials so that the resulting product is practically uniform in its component parts throughout the entire body thereof.

One great advantage of my process is that from a single heat of the iron and steel, each and every tapping of the molten metals into a ladle may be exactly the same, as regards both proportions of the metals and the uniformity of admixture, or each tapping may differ irom the others in these respects.

Furthermore, the pig iron and the carbon steel being melted in separate cupolas or furnaces, the conditions to the requirements of each metal in the matter of melting, the operation of the two cupolas in this regard being entirely independent of each other. By my processabsolutc uniformity, as regards the proportions of iron and steel, can be maintained throughout the entire heat or vary at Wlll during each heat, or the proportions can be maintained uniform throughout anynumber of heats where a large product is required possessing the same characteristics and proportions of iron and steel. 7

It will be understood that my invention is not directed to the production of any new kind of metal of new composition, but as a process whereby a skilled metallurgist, knowing the composition of the materials which he desires to mix or unite in a homogiven composition, may be geneous mass of a assured of producing the desired result.

other ,Words, it iswell known. to mctallurgists'lhat the average run of pig iron will contain-about three and one hall per. cent ol' carbon, one half of one per cent. ol manganese and one to three per cent. of silicon, while or- I dinary carbon steel will contain two-maths of one per cent. of carbon, six tenths of one per cent. of manganese and six lumdrodths ol' one per cent. of siiicon. Now it it is desired to produce a metal from a mixture of the pig iron and carbon steel having a desired. and predetermined proportion or these (.lill'erent ingredients, according to the use to which themetal is to be put and the way it is to be treated in'casting, any skilled metallurgist in each can be adapted I would know to a practical certainty just what proportions of the pig iron and carbon steel should be used, but if the iron and steel were melted in a single cupola, no metallurgist can ever be certain of form mixture and indeed such umformity is almost impossible for reasons hereinbefore fully stated. By my process, howeveryproviding for the melting of the pig iron and the carbon steel in separate cupolas before bring ing the same together, the composition of the final product, by mixing the is rendered practically certain, while the ca: bon, manganese and silicon, or other ingredient would be distributed throughout the mass with practically perfect uniformity. The purpose of adding the white iron to l the composition is also well understood in metallurgy, being simply to reduce the meltl ing point and therefore increase the fluidity of the steel so as to effect a more thorough, I intimate and uniform distribution of the I carbon, manganese and silicon. Other kinds of iron may be usedv for the same purpose, but I prefer the ordinary white iron because of its recognized superior characteristics. The necessity of bringing the two metals together at temperatures which result in a mean that liqueiies both in the ladle, makes it important to thus reduce the melting I point of the latter and increase the fluidity of the mixture, as \Vlil be readily understood. [1 il'laving tlius l'ullydcscribed my invention,

what I claim, and desire to secure by Letters In the art of making semi-steel castings, the process which consists in mel ing gray pig iron and carbon steel in separzj ie cupojlas or furnaces, adding to the steel while melting about ten per cent. of white pig 11011, l introducing into a mixing receptacle prede- I tcrmined portions of the molten metal from each eupola or furnace, thoroughly mixing the same together in a molten state, and linally pouring the same directly into molds, isubstantially as and for the purpose described.

JAMES C. DAVIS.

O. L. \Voon,

l Witnesses:

l G. Y. DANKWARD.

molten metal producing a uni- 

